Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
3 ~.3064~
1 BACKGROUND OF THE INVENTIO~
The newspaper printing system disclosed and claimed
in the application relates to improvements in printing pressure
of the type disclosed in Canadian Patent No. 938,832 issued
December 25, 1973 and relates specifically to simplifying
existing lithographic printing processes for publishing news-
papers, books and the like on coarse, rough, absorbent pulp
paper. Newsprint type paper is very coarse having a large amount
of loose fibers on the surface of the paper.
Heretofore, attempts to achieve quality printing on
both sides of a web have utilized opposed offset blankets mounted
on cylinders. The blankets accumulate ink and tend to collect
loose fibers and lint and thereby has been limited in use on
newsprint paper because of the accumulation of ink and lint on
the blankets and in the inking train necessitating cleaning
of the blankets on the blanket cylinders.
Heretofore, presses which have attempted to print
direct.~y on both sides of newsprint, as disclosed in Canadian
Patenk No. 938,832 and U.S. Patent No. 926,102 have utilized
~ ~o conventional inkers.
;; Conventional inkers for lithographlc printing plates
used for printing on newsprint which have achieved "commercial"
acceptance generally comprise from two to four form rollers
which are positioned in rolling engagement with the printing
plate. Each of the form rollers is usually in rolling engage-
ment with one or more vibrator rollers to which ink is applied
by several rollers in a train of rollers o varying diameters
arranged in pyramid fashion. Ink is delivered to the train of
rollers over a ductor roller which oscillates into and out of
3~ engagement with a film of ink formed by a doctor blade urged into
~.~ 3~
1 engagement with the hard surface on an ink fountain roller
by numerous ink keys.
The ink film formed on the ink fountain roller has been
too thick and too irregular for application directly to a
printing plate for quali-ty printing. These inkers which include
a multiplicity of rollers are intended to reduce the thickness
of the lnk film and to deliver a film of uniform thickness to
the printing plate. However, since the ink film on each of the
rollers is not totally replenished on each revolu-tion of the
form roller; image ghosting and ink accumulation and starvation
is not completely eliminated. Thus, streaks and uneven ink
distributions are produced on the product due to the ghosting
and ink accumulation and/or starvation.
The multiple form roller, conventional inkers require
complex drive trains and are relatively expensive to purchase
initially and to maintain thereafter.
Other types of inkers which have attempted to meter
ink from a transfer roller to a form roller have utilized a
doctor blade to remove all of the film Gf feedback ink from the
form roller prior to replenishing the ink film. Since mos-t
form rollers are resilient, the contact of the doctor blade to
the form roller surface may score the form roller and wear out
the blade and roller causing an uneven film of ink.
The invention described herein addresses the problem
of direct printing with opposed plates engaging opposite sides
of a web of newsprint simultaneously without the use of offset
blankets by utilizing inkers which control accumulation of ink
and dampening fluid to control accumulation of lint, while
eliminating the conventional train of rollers in the inking
systemj eliminating the necessity for the consumption
3L13V64~
1 of excessive power and fur-ther reducing and eliminating
numerous adjustments and areas of ghos-ting and ink accumulation
and starvation which produce undesirable variations on the
product being printed.
Devices of the type disclosed in U.S. Patent No.
3,926,114 were devised to remove all the unused portion of ink
and dampening fluid from the form roller prior to forming a
new film of ink by metering the ink between the form roller
and a transfer roller. There may be considerable wear on the
1~ ink removal blade and the roller in this type of device.
Also, it is extremely difficult to form an ink film which is
sufficiently thin by using a doctor blade when metering
newsprint ink.
Inking devices of the type disclosed in U.S. Patent
No. 2,2~0,762 employ rollers having ca~ities formed in the
surface to meter ink onto a form roller for application to a
printing plate.
An improved inker and dampener structure is described
herein for applying a controlled film of ink to both sides of
newsprint by direct lithography as the web of newsprint moves
directly between two opposing lithographic plates. The inker and
dampener cooperate toyether on a single form roller to eliminate
excessi~e accumulation of ink and dampening fluid to eliminate
accumulation of lint and fiber on the plate or inking and dampen-
ing system.
~ pair of opposing plates simultaneously engage opposite
sides of a newsprint web to print thereon. Substantially
identical inkers and da~npeners apply ink and dampening fluid to
each opposing plate as hereinafter described.
44
1 SUMMARY OF THE INVENTXON
The inker comprises a metering roller and a transfer
roller, each having an oleophillic surface urged into pressure
indented relationship. The metering roller and transfer roller
are adapted to meter an excess of low viscosity ink at the nip
between the metering roller and the transfer roller such that a
substantially uniform quantity of ink is metered onto the
surface of the transfer roller. An ink storage roller may be
positioned in pressure relation with the transfer roller to
further condition the quantity of ink to assure that the
quantity of ink is substantially uniform and continuous. The
quantity of ink is then sheared and metered at a nip between
the transfer roller and a single inking form roller~ By con-
trolling -the speed between the form roller and the transfer
roller, slippage occurs thus forming a thin, substantially
uniform, calendared, smooth layer of ink on the single inking
form roller.
The film of ink suppIied to the single inking form
roller is further conditioned by a material conditioning roller
to produce a smooth matte finish thereon. The material condition-
; ing roller has essentially the same affinity for ink as does the
form roller and thus splits the film to form a matte finish on
.: the ink layex.
The matte finish is readily adapted to acceptingdampening fluid for use in a lithographic printing system. A
dampening system having a transfer roller with a hydrophillic
surface and in pressure indented relation with a resiliently
covered metering roller transfers dampening fluid to the matte
finish of the ink on the form roller prior to movement of the
- 30 ink and dampening fluid layer into enyagement with the lithographic
~13~)64~
1 printing plate. The ink and watex film is transferred to im~ye
areas on the printing plate and the dampening fluid only to non-
image areas such that lithographic printing is performed.
After the layer of ink on the form roll moves away from
the printing plate -there will be ghosted or depleted areas of
ink which are reduced by an ink storage roller which accumulates
ink and supplies it to the ghosted or areas starved of ink
prior to the layer of ink moving into the nip between the form
roller and the transfer roller to more fully replenish the
depleted film of ink.
As an irregular film of ink moves from the ink storage
rollers on the single inking form roller, it marries again with
a fresh uniform quantity of ink on the transfer roller to form
a substantially uniform film of ink on the form roller by
removing ink from the transfer roller to replenish the depleted
areas on the form roller. The transfer roller continuously
furnishes a uniform quantity of ink to the form roller and the
irregular feedback film, remaining on the transfer roller as the
form roller removes ink from th~ transfer roller, moves back to
the flooded nip between the transfer roller and metering roller
to be remetered.
This type of inker is particularly adapted for applying
newsprint type ink in inking processes such as Di-Litho
(registered tra~emark of American Newspaper Publishers Associa-
tion/Research Institute) for printing direct on a lithographic
plate with water for application on both sides of newsprint.
A primary object of the invention is to provide a non-
accumulative simplified printing system which continuously
provides a substantially uniform thickness of ink with a single
3~ inking form roller to opposing lithographic prin-ting plates
on each side of a newsprint web.
~3~16~4
1 Another object of the invention is to provide a pair
of opposing printing plates for simultaneously printing by
lithography on an absorbent, porous newsprint web moving between
the plates.
A still further object of the invention is to provide
an inking system which continuously provides precision control
of the thickness of the ink film eliminating ghosting and a
resulting color variation of the printed imagesO
Another object of the invention is to provide an inking
system to use with low viscosity ink which will provide a sub-
stantially uniform layer of ink which is readily acceptable to
receiving dampening fluid for application on a printing plate.
A further object of the invention is to provide a
simple and efficient inking system capable of forminy a thin,
continuous and substan~ially uniform thickness of ink which
eliminates the necessity of power consuming techniques.
A still further object of the invention is to provide
an inking apparatus which has a single point of control of the
thickness of ink which eliminates streaks and imperfections
2~ from the lint and paper fragments and color variation while
minimizing lag time of adjusting the ink film.
A still further object of the invention is to provide
an inking system and a dampening system, each being particularly
adapted to prevent accumulation of ink and dampening fluid in
the inking system and to prevent misting of ink and accumulation
of lint.
Other and further objects will become apparent upon
referring to the following detailed description and the attached
drawings.
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644
1 BRIEF DESCRIPTION OF THE DRAWINGS
Drawings of a preferred embodiment of the invention
are annexed hereto so that the invention may be better and more
fully understood, in which:
Figure 1 is a diagrammatic illustration of the
newspaper printing system;
Figure 2 is a diagrammatic illustration of a multi-
unit newspaper printing system;
Figure 3 is a diagrammatic illustration of the inking
system illustrating the various films of ink and dampening
fluid;
Figure 4 is a front elevational view illustrating the
ink metering and transfer rollers and support structure;
Figure 5 is a cross sectional view taken along line
5-5 of Figure 4; and
Figure 6 is an enlarged diagrammatic view of the web
engaged by the opposed plate cylinders.
Numeral references are employed to designate like
parts throughout.the various figures of the drawings.
DESCRIPTION OF A PREFE~RED EMBODIMENT
In Figures 1 and 2 of the drawings, the numeral 1
generally designates a newspaper printing system for simultaneously
applying ink and dampening fluid to opposed lithographic printing
plates Pl and P2 of a special simplified newsprinting press.
The water applicatox is a dampener 200 such as the type disclosed
in United States Patent No. 3,937,141, entitled "Dampener for
Lithographic Printing Plates" which issued February 10, 1976 to
Harold P. Dahlgren. The dampener may, i~ expedien-t to do so,
be of the type disclosed in U.S. Patent No. 3,168,037, issued
30 February 2, 1965.
~ ,.
;44
1 The ink applicator 100 is of the type disclosed in
my co-pending Canada application Serial No. 325,681 entitled
"Reversible Newspaper Press", filed April 18, 1979.
As illustrated in Figure 1 inkers 100 and 100' and
dampeners 200 and 200' apply ink and dampening fluid to form
rollers 90 and 90' respectively which apply a water-in-ink
emulsion to plates on cylinders Pl and P2, respectively, to
print lithographically to each side of web W of newsprint.
Web W is a coarse sheet of porous, absorbent and
resilient paper having loose fibers and uneven surfaces.
Plate cylinder Pl, Figs. 3 and 6, has a resilient
cover 140 secured on core 142 to support plate 112. Plate
clamps 144 of typical construction are provided to secure plate
112 to cylinder Pl.
As best illustrated in Figure 4, ink applictor 100
comprises spaced side frames 2 and 4 joined by tie bars (not
shown) forming a strong rigid structure for supporting form
roller 90, ink transfer roller 10, ink metering roller 12 and
ink pan 14. Side frames 2 and 4 may be the side fra~es of the
basic system or may comprise inker side frames connectable
to side frames of the basic system.
Throw-off links 1~ and 18 are pivotally secured by stub
shafts 20 and 22 to the respective side frames 2 and 4. Throw-
off cylinders 24 and 2~ are pivotally connected between side
frames 2 and 4 and throw-off links 16 and 18, respectively, for
pivoting throw-off links 16 and 18 about stub shafts 20 and 22
for moving ink transfer cylinder 10 into position, as will be
hereinafter more fully explained, for delivering ink to a single
form roll in a lithographic printing system.
A skew arm 28 is mounted for pivotal movement of one end
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~, ,, ~
;44
1 of a metering roller 12 about the axis of ink transfer xoller 10.
As diagrammatically illustrated in Figure 4, skew arm 28 is
rotatably secured to stub sllaft 30 extending between link 18 and
skew arm 28 adjacent an end of ink trans~er roller 10.
Skew arm 28 and throw-off link 16 have grooves 28a and
16a, respec-tively, formed in the inner surfaces thereof in which
blocks 36, carrying self-aligniny bearings 38, are slidably
disposed. Blocks 35 are rigidly secured in the upper portion of
grooves 28a and 16a be screws 37 to provide suitable suppor-t
1~ for shafts 31 and 32 of the ink transfer roller 10. Suitable
means such as resilient springs 40 between blocks 35 and 36 urge
blocks 36 longitudinally of skew arm 28 and throw-off link 16
in a direction away from the longitudinal axis of transEer roller
10. A pressure adjustment screw 42 urges block 36 longitudinally
of skew arm 28 and throw-off link 16 against the bias of
springs 40. Stub shafts ~4 and ~6, extending outwardly from
opposite ends of metering roller 12, are received in self-
- aligning bearings 38 to rotatably secure metering roller 12 in
pressure indented relation with transfer roller 10. Stub
shafts 31 and 32, extending outwardly from opposite ends of
transfer roller 10, are received in bearings 39 in blocks 35.
It should be readily apparent that rotation of pressure
adjustment screws ~2 will move opposi-te ends of metering roller
12 relative to the axis of transfer roller 10 for controlling
pressure between transfer roller 10 and metering roller 12.
As illustrated in Figure 5, suitable means is provided
for establishing and maintaining a desired angular relationship
between throw-off link 18 and skew arm 28. In the form of the
invention illustrated in Figure 5, an adjusting screw 50 is
rotatably secured to skew arm 28 and extends through threaded
_g_
1~3~
1 apertures in pivotal blocks 52a and 52b. Blocks 52a and 52b are
pivotally secured to lug 54 on arm 28 and lug 56 on link 18. By
adjusting screw 50, the spacing between lugs 54 and 56-is
adjusted to move skew arm 28 relative to link 18 abou-t shaft 30.
Side frames 2 and 4 have suitable adjustable stop
means such as stop blocks 5 havlng set screws 5a extending there-
through for enga~ing throw-oEf links 16 and 18 when rods of
throw-off cylinders 24 and 26 are extended for establishiny a
desired pressure relationship between the transfer cylinder 10
and an ink coated form roller 90 arranged to transfer ink to a
lithographic plate 112 on plate cylinder Pl, as will be herein-
- after more fully explained. Stop means such as stop blocks 6
having set screws 6a secured thereto provide an o~f-impression
limit when piston rods of throw-off cylinders 24 and 26 are
retracted to move the transfer roller 10 away from the surface
of form roller 90. Stub shaft 32 has a brake disc 51 secured
thereto and friction pads 53 are pivotally secured to support
55 secured to arm 28 to control the speed of transfer roller 10
when it is driven by frictional engagement with form roller 90.
Stub-shaft 31, extending outwardly from the end of
transfer roller 10, has a gear 60 rigidly secured thereto by
screws 61 which is in meshing relation with a gear 62
rotatably secured by a bearing 45 disposed on shaft 44.
Gear 62 is secured in meshing relation with gear 64
` on shaft 58 rotatably secured to housing ~1 through a clutch
assembly 66 of a type such as a Morse one-way clutch. Shaft 58
is secured to the shaft of a variable speed drive means such
as a variable speed electric gear--motor 69. It should be
appreciated that gear-motor 69 may be replaced by other drive
rneans such as gears, sproc]ce-ts, or pulleys arranged to be
--10--
- 1~3~)6~4
1 driven from the printing press drive, preferably throuyh a speed-
reducing gear box or similar variable speed control apparatus.
Shaft 44, eY~tending outwardly from the end of metering
roller 12, has a gear 70 secured thereto in meshiny relation with
a gear 71 secured to and driven by shaft 58.
Power supply line 80 is connected through a variable
rheostat 8~ to the terminals of motor 69 so that motor may be
run at variable speeds to control the speed of rotation, and,
consequently, surface speeds of transfer roller 10 and metering
roller 12 independently of the press drive. If it is deemed
expedient to do so motor 69 cauld be replaced by a variable
speed coupling which connects shaft 58 to the press drive means,
as hereinbefore described.
Clutch assembly 66 allows transfer roller 10 to be
driven by gear-motor 69 at a minimum speed ratio relative to
metering roller 12, for example 1:1, and allows transfer roller
10 to be over-driven by form roller 90 at higher speeds without
driving the metering roller 12 at a faster speed which may tend
to sling ink 14a out of pan 14.
It shouid be appreciated that clutch 66 can be deleted
to allow drive of the transfer roller 10 positive~y from the
gear-motor 69.
An ink storage roller 82, illustrated in Figure 3, is
preferably a vibrator or oscillator roller. Ink storage roller
82 is adapted to equalize areas of excess ink on transfer roller
10 in a manner to be more fully explained hereinafter.
~uitable means is provided for delivering an abundant
supply of ink to the ink metering nip N between adjacent surfaces
of transfer roller 10 and metering roller 12. In the particular
embodiment of the invention illustrated in Figure 3, a por-tion
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- 113~6~
1 f the surface of metering roller 12 is submerged in ink 14a in
ink pan 14.
Ink l~a preferably comprises a low viscosity ink
such as the type employed in direct lithographic printing such
as newsprint type ink.
The transfer roller 10 is preferably hard and has an
exterior surface which may be smooth or textured and which is
ink receptive; that is, oleophillic. Ink transfer roller 10
may, therefore, have an exterior surface of materials such as
copper, or plastic. The surface of transfer roller 10 may be
either hard or resilient. Since form roller 90 has a resilient
surface, the surface of transfer roller 10 may be hard or
resilient.
Metering roller 12 preferably comprises a hollow
tubular sleeve having stub shafts 44 and 46 forrned thereon. A
resilient cover 12c is shown secured about the outer surface
of the sleeve. The material of metering roller cover 12c is
selected so as to be oleophillic and the surface may be smooth
or textured, hard or resilient. However, at least one o:E ink
transfer rollerlO and metering~ler 12 is made to be resilient.
To reduce the tendency of ink to accumulate adjacent
the ends of transfer roller 10, metering roller 12 is longer
then transfer roller 10 such that ends of the metering roller 12
extend beyond the ends of transEer roller 10. The transfer
- roller 10 is preferably longer than form roller 90 to minimize
accumulation of excess ink adjacent ends of form roller 90.
It should be readily apparent that, if desired, the
material oE transfer roller 10 and metering roller 12 may be
reversed such that metering roller 12 has a hard surEace and
-transfer roller 10 has a resilient cover, or both could be
resilient.
~130f~44
Form roller 90 is preferabl~ cu-t to be the same length
as the printing plate 112 or plates to also minimize accumulation
of excess ink which may tend to build on the form roller if lonyer
than the printing plate.
Referring to Figure 3 of the drawing, transfer roller
10 is preferably positioned in pressure indented relation with
a single form roller 90, having a metal tubular core 91 to the
ends of which are secured stub shafts extending outwardly
therefrom and rotatably journaled in bearings 92 carried by the
side frames 2 and.4.
Form roller 90 has a smooth resilient outer cover 96
which may be non-absorbent or absorbent.
In one embodiment, form roller 90 may have a resilient
non-absorbent surface. Another embodimènt of form roller 90
includes a resilient surface and has a molleton type cover which
absorbs ink and will reject dampening fluid.
An ink s-torage roller 94, preferably a vibrator .
roller is adapted -to remove ink from areas 128" from ink film
128 on the surface of form roller 90 and add the ink to the
~0 depleted areas 128' thereby creat~ng a more uniform film of ink
on the surface of roller 90 moving from the nip 120 toward
nip 108.
A material conditioning roller 86, preferably a
vibrator roller, is rotatably supported on shaft 86a in blocks
86d and is adapted to condition and smooth the surface of ink
film 100" to make the film more receptive to accepting dampening
fluid. Screws 86b and 86c are adapted to urge blocks 86d and
roller 86 into pressure indented relation with form roller 90.
The surface of material conditioning roller 86 is preferably of
similar material to that of form roller 90 such that the surface
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1~3~t~44
1 has the same affinity for ink as does the surface of form roller
90 .
As the ink film 100" emerges from the nip 106 between
form roller 90 and transfer roller 10, it is slick, and
calendared. A slick film of ink is not particularly receptive
to dampening fluid since the surface tension of the molecules
of ink may reject the thin layer of dampening fluid to be
applied by dampener 200. Material condi-tioning roller 86 will
receive a portion of the film 100" of ink thus splitting the
film 100" of ink and producing a film lOO"'on roller 86 thus
leaving film lOOa with a matte finish having microscopic
indentations. The maite finish on film lOOa will more readily
` accept the thin layer of dampening fluid 216 due to molecular
attraction which is now greater than the surface tension oF
the dampening fluid moved into engagement therewith in film 204
on dampening fluid transfer roller 210.
Material conditioning roller 86 and ink storage rollers
94 preferably have different diameters to eliminate repetition
of a pattern such that as they rotate ink will be properly
applied or extracted and redistributed on the surface of roller
.
:' 90.
Vibrator rollers 82, 86 and 94 are preferably coppPr
or plastic covered and are provided t~ith drive means (not shown)
to oscillate the rollers in a longitudinal direction. Suitable
oscillator drive means is well known to persons skllled in the
printing art and further description is not deemed necessary.
Rotation of rollers 94 and 86 is provided through frictional
contact with adjacent surfaces. Roller 82 is preferably driven
by a gear in meshing relation with a gear secured to roller 10.
3~ Dampener 200 is diagrammatically illustrated in
-14-
4~
1 Figures 3 and 5 as described in Patent No. 3,937,141 cornprises a
hydrophillic transfer roller 210 on shaf-t 210a and a resilient
me-tering roller 212 on shaft 212a, mounted in a similar manner
to inker 100. Meteriny roller 212 meters dampeniny fluid 21~a
from pan 21~ onto transfer roller 120 through flooded nip Na.
Controlled pressure between adjacent surfaces of rollers 210 and
212 forms a thin layer of dampening fluid 20~ which is metered
through dampening fluid transfer nip-106a on-to the matte finish
of ink film lOOa on the surface of form roller 90.
A vibrator roller 93, not unlike rollers 94 and 86 and
illustrated in Figure 1, may be used to further smooth the ink-
water film 216, if desired.
As illustrated in Figures 1, 3 and 6, a web W moves
between resiliently supported plates on cylinders Pl and P2
carrying lithographic printing plates 112 and 112'. The structure
of inking syste~ 100' and dampener 200' supplying ink and
dampening fluid to plate cylinder P2 is substantially the same
as inker system 100 and dampener 200 heretofore described. Like
parts of inker 100' and dampener 200' are designated by like
numerals having a prime mark thereon in the drawing for
descriptive purposes.
As best illustrated in Figure 6, web W is mo~ed through
printing nip Np between plates on cylinders P1 and P2. The
surfaces Ws of web W are compressed in segment Wa in printing
nip Np. Ink on ima~fe areas 122 is absorbed by the porous,
absorbent web W of newsprint at printing nip Np as indicated by
dashed outline of inked areas 150 past the nip Np. The web W
acts as a resilient absorbent blanket to allow the ink on the
resiliently supported plates on cylinders Pl and P2 to be
printed without significant dot gain. The absorbent web W
644
1 therefore prevents meshing of dots of ink since the ink is
absorbed rather than printed on the surface of the paper and
later dried. The web W absorbs practically all of the ink from
image areas 122.
The operation and function of the apparatus herein-
before described is as follows:
Pressure between ends of transfer roller 10 and
metering roller 12 is adjusted by rotating pressure adjustment
screws 42.
Since long rollers urged together in pressure indented
relation tend to deflect or bend, pressure adjacent centers of
such rollers is less than pressure adjacent ends thereof.
Pressure longitudinally of rollers 10 and 12 is adjusted by
rotating screw 50 and rotating skew arm 28 about the axis of
transfer roller 10 to a position wherein a desired pressure
distribution longitudinally of ro~ers 10 and 12 is obtained.
Adjustment screw 5a is posi-tioned to engage throw-
off links 16 and 18 for establishing a desired pressure between
transfer roller 10 and form roller 90.
The relative surface speeds of rollers 10 and 12 and
of rollers 10 and 90 can be regulatea by manipulating rheostat
84 as has been hereinbefore explained.
Dampener 200 is adjusted in a similar manner as inker
lOo for applying dampening fluid to form roller 90.
For the purpose of graphically illustrating the novel
function and results of the process of the mechanism herein-
before illustrated and described, a diagrammatic view of the
metering roller 12, the transfer roller 10 and the form roller
90 i5 shown in Figure 3. Ink and water films shown are exaggera-
ted for clarity.
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~1~[)64~
1 As shown in Figure 3, metering roller 1~, when
employed to deliver ink to a printing pla-te 112 on print
cylinder Pl is preferably a resilient surfaced roller having a
smooth surface 12c thereon and has the lower side thereof
immersed in ink 14a in pan 14. The metering roller 12 is
rotatably mounted in pressure indented relation with transfer
roller 10, and the pressure between adjacent roller surfaces
is adjusted by screws 42 and 50, as hereinbefore described,
so that the surface of transfer roller 10 is actually impressed
into the surface of roller 12 at ink metering nip N.
As the surface of roller 12 rotates toward the ink
metering nip N between rollers 10 and 12, a relatively heavy
layer 101 of ink is picked up and lifted on the surface of
roller 12. At the point of tanyency, or cusp area at the inX
metering nip N, between the rollers 10 and 12, a bead 102 of ink
is piled up forming an excess of ink. The greatness of the
excess of ink forming bead 102 is reyulated by virtue of the
fact that excessive ink will fall back into the pan 14 by
yravity, thus, virtually creatiny a waterfall of ink, and by the
surface speed of metering roller 12. The bead 102 becomes a
reservoir from which ink is drawn by transfer roller 10. As
rollers 10 and 12 rotate in pressure indented relation, a layer
of ink is sheared and/or metered between adjacent surfaces of
the two rollers separated by a thin lubricating layer of ink 103.
Since the transfer roller 10 has a smooth, oleophillic surface
thereon, a portion of the film 103 adheres to the surface of
roller 10 to form a quantity 104a. the remaining portion 105
thereof being rotated back or fed-back in the pan 14. The
quantity of ink 104a is distributed on the surface of roller
10 by reason of the rotating, squee~ing action between rollers 10
11~0~i44
- 1 and 12 a-t their tangent point at ink metering nip N. Ink
storage roller 82 splits ink lO~a and receives ink 104' which
is added to ink 104a again to further assure smooth uniform
thickness of ink 104 on transfer roller 10.
The film of ink 104 rides on the surface of roller 10
and comes in contact with the film 130 of ink on form roller
90 at the tangent point or ink transfer nip 106 between trans~er
roller 10 and form roller 90.
At ink transfer nip 106, it will be observed that
1~ transfer roller 10 is impressed into the resilient surface of
form roller 90 and that the film of ink 10~ has an outer
surface 108, contacting the ink fi~lm 130, and an inner surface
110 adhering to the surface of roller 10. The outer surface 108
of film 104 and the outer surface 131 of the film of ink 130 on
form - roller 90 are urged together LO create a hydraulic
connection between rollers 10 and 90 as they rota-te in close
relationship, but there is no physical contact be-tween the
adjacent roller surfaces.
It is an importan-t fact to note that -the ~elatively
thick quantity of ink 104 requires roDers 10 and 90 to be rotated
at different sur~ace speeds, as will be hereinafter explained.
Preferably, the form roller 90, which is normally rotated at
the same surface speed as the printing plate 112 on cylinder Pl,
and press driven~ is rotated at a surface speed greater than
the surface speed of roller 10. By regulatin~ the differential
sur~ace speed between transfer roller 10 and applicator roller
90 the amount of ink applied to the plate 112 may be regulated.
Within limits, as will be hereinafter more fully
explained, if the sur~ace speed of transfer roller 10 is
3~ increased the ink film 10~ is presen-ted at the ink transfer nip
-18-
~L3~6~
1 106 at a faster rate and more ink is transferred to the surface
of roller 90 and to lithographic printing plate 112 on cylinder
Pl, and the opposite i5 true, if the surface speed of ink
transfer roller 10 is decreased.
The film of ink, existent between adjacent surfaces
of rollers 10 and 90, permits rollers 10 and 90 to be rotated
at different surface speeds in sliding relationship, because
the film of ink actually provides lubrication which permits
slippage between adjacent surfaces of rollers 10 and 90
1~ without frictional deterioration. By reason of the slippage
between rollers 10 and 90, the ink 104 is calendared, smoothed
out, metered and distributed by shearing ink 104 between adja-
cent surfaces of roller 10 and the ink film 130 on form roller
90 to create ink film 100". The thickness of ink film 100" is
controlled by pressure between metering roller 12 and transfer
roller 10 and the speed of transfer roller 10.
Transfer roller 10 preferably is driven at a surface
speed which is within a range of for example, several hundred
feet per minute slower than the surface speed of form roller 90.
For example, if a printing press has paper travelling there-
through at a surface speed of 1200 feet per minute the surfaces
of printing plate 112 and form roller 90 will ordinarily have
surface speeds of 1200 feet per minute. The surface speed of
transfer roller 10 may however rotate at a surface speed in a
range between 50 feet per minute and 100 feet per minute to
create adequate film 100'l for printing.
Ink 104 and film 130 are combined at ink transfer
nip 106 and will split when sheared as rollers 10 and 90 rotate
away from ink transfer nip 106. The fresh film 100" of ink
adheres to the surface of form roller 90. Ink rejected by form
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1~1L3~)6'~
1 roller 90 forms a feedback film 116 of ink which adheres to th~
surface of the transfer roller 10 and is conveyed back to the
bead 102 of ink adjacent ink metering nip N to be remetered.
Feedback film 116 is not necessarily uniform because the starved
areas 128' on form roller 90, from which ink was removed by
image areas on the plate 112, removed differen-t quantities of
ink from ink quantity 104 in order to remeter film 128 on form
roller 90. Film 128 has starved areas 128' from ink removed by
image areas 122 on plate 112, thus r~ndering film 128 irregular.
As the film 100" of ink on the surface of form roller
90 moves from ink metering nip 106 adjacent transfer roller 10,
the film 100" is substantially uniform as non-uniform film 130
is combined with ink quantity 104 carried on transfer roller 10.
Film 130 accepts ink from film 104 in the starved or depleted
areas 128'. The transfer roller 10 is caused to rotate at a
speed which satisfies the need for ink by form roller 90 by
overriding clutch 66 and brake 55. The depleted par-tion or
feedback film 116 is returned to the abundant or excess supply
of ink at bead 102 between metering roller 12 and transfer roller
10 to replenish the ink quantity.
It has already been explained that the ink film 130 is
smoothed out, distributed, metered, and regulated at the ink
transfer nip 106 between transfer roller 10 and form roller 90.
Material conditioning roller 86 splits film 100", taking on a
film 100"' to produce a matte finish on ink film lOOa. Any
irregularities or streaks in film 100" will be spread and
equalized to form film lOOa of very uniform thickness.
- The interfacial tension between the outer surface of
the less viscous dampening fluid film 204, by reason of molecular
attraction between the surface of the more viscous ink film lOOa,
~ -20
~13~6~g~
j causes a portion 216 of the smooth and regulated film 204 of
dampening fluid to be added to the surface of ink film lOOa,
which in turn is transferred to the plate at the tangent point
between the plate 112 and :Eorm roller 90 at inkiny nip 120.
The lithographic printing plate 112 has hydrophillic,
or water liking, non-image areas 121 and oleophillic, or ink
receptive, image areas 122 formed on the surface thereof.
At the nip 120 between applicator roller 90 and print-
ing plate 112 on cylinder Pl, the ink-water emulsion 216 is
1~ split, forming thin films 125 of ink and water over oleophillic
surfaces 122 on the printing plate. The layer 216 of dampeneng
fluid and ink is carried on and in the film lOOa of ink and is
also distributed to form a thin film 126 of dampening fluid
over hydrophillic areas 121 of the printing plate.
No appreciable amount of dampening fluid remains on the
surface of form roller 90 which is moving away from the nip 120,
but such dampening fluid as does remain thereon is transferred
with the ink film 128 to the ink film 130a on the ink s-torage
roller 94 where the dampening fluid can be distributed and
dissipated and/or evaporated to such an extent as to be of no
consequence in the inking system. Without roller 94, water and
ink variations cause poor distribution of ink quantity 104 to
be applied to form roller 90; that is, depleted areas tend to
remain depleted.
Ink film 128 remaining on form roller 90 is combined
with film 130a on ink storage roller 94 ancl split and collected
on roller 94. Ink on roller 94 is added to depleted areas 128'
in film 128 thus reducing the effect of ghosted areas in film
128 by forming a more uniform film 130 before re-entering nip
106.
6~
1 The dampening fluid 216 is applied in substantially
the same manner. ~n excess of dampening fluid 201 is supplied
to form bead 202 to form a metered film 204 of dampening fluid
which is applied tG ink film lOOa on form roller 90 at nip 106a
forming a water-in-ink emulsion 216. The remaining film 217
of dampening fluid is returned to bead 202 to be re-metered at
nip Na.
From the foregoing it should be readily apparent that
the improved apparatus for applying ink to opposed printing plates
offers control of metering at ink metering nip N to provide a
film 104 Gf ink of precisely controlled thickness by adjusting
pressure between transfer roller 10 and metering roller 12 and
further by controlling surface speeds of rollers 10 and 90
relative to each other. The ra-te at which the metered film 104
of ink is offered to film 130 of ink on form roller 90 at ink
transfer nip N and also the hydraulic force for obtaining the
desired film split is controlled.
To eliminate conditions which could cause accumulation
of ink rendering it impossible to form a quantity oE ink 104 of
precisely controlled thickness the specific roller arrangement
provides for replenishment of ink which is fed-back in the form
of ink film 116 on transfer roller 10 moving away from the inlc
transfer nip 106. Thu~, the effect of the unused depleted film
of ink not accepted by printing plate 112 is eliminated from the
inking system by returning film 116 to the flooded ink metering
nip N and is not left to accumulate on transfer roller 10 as in
prior art devices.
It should further be appreciated that either the
transfer roller 10 or meterlng roller 12 could be geared to the
press drive, or driven by an lndependent drive means, for
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~30644
1 establishing the conclitions hereinbefore described for a
specified speed range.
It should be appreciated that transEer roller 10 may
be oscillated laterally along its axis to further smooth ink
films 130 and 100".
Inker ]00' and dampener 200' supply ink and dampening
fluid to plate 112' on cylinder P2 in a similar manner as
described heretofore for plate cylinder Pl.
It should be appreciated that under certain operating
1~ conditions metering roller 12 could be replaced by a stationary
non-rotating metering member to meter ink on ink transfer roller
10 where an excess supply of ink is supplied to the transfer
roller.
It should be readily apparent tha-t the heretofore
described invention provides a simplified plate to pla-te printer
with continuous duty inkers and dampeners to produce an improved
image on newsprin-t type paper.
While ~e printing system hereinbefore described is
particu]arly adapted for printing ink of low viscosity onto
~g rough, porous paper known as newsprint, it should be readily
apparent that different types of ink and paper may be employed
with the system withouk departing from the basic concept of the
invention. Further, the resilient packing under one or both of
the printing plates may be omitted, if it is deemed expedient to
do so, to achieve a desired paper pressure.
While a preferred embodiment of the invention has been
hereinbefore described and illustrated in the attached drawings
it should be appreciated that other and further forms of the
apparatus can be devised without departing from -the basic
3~ concept thereof.
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